New Rear Breaks are thumping?

1997 Cavalier, I am taking it back today at 3pm. I have had a brake job done before and I never had this happen. I wonder what the heck they did, I have had oil changes there for quite a few years. I thought I could trust them. Guess not.
Yes that was the wording on the receipt.
Exact words:
Rear Brake Job, Drum brakes
We serviced the break self adjusters.
We machined the brake drums.
We installed new “Heavy Duty” Rear Brake Shoes and
installed the brake drums. We adjusted the brakes and we
test drove. The brakes are working properly at this time.
No noise was detected at this time.
THOse are the exact words on the receipt. Sure the brakes work but how could they not hear those cluncks and thumping noise everytime you apply the brakes.
It went to them with a slight sweak when applying the brakes and leaves with this type of noise?@! Just because I am a woman doesn’t mean I am deaf.
Please tell me what they probably did to my poor little Cavalier!?
Laurie